package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import com.hmdp.dto.Result;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import lombok.extern.slf4j.Slf4j;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.connection.stream.*;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import java.time.Duration;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.concurrent.*;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author wj
 * @since 2021-12-22
 */
@Service
@Slf4j
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Autowired
    private ISeckillVoucherService iSeckillVoucherService;

    @Autowired
    private RedisIdWorker redisIdWorker;

    @Autowired
    private StringRedisTemplate stringRedisTemplate;

    @Autowired
    private RedissonClient redissonClient;

    private static final DefaultRedisScript<Long> SETCKILL_SCRIPT;
    // 类加载初始化 lua 脚本
    static {
        SETCKILL_SCRIPT = new DefaultRedisScript<>();
        SETCKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SETCKILL_SCRIPT.setResultType(Long.class);
    }

//    private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1000);

    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    @PostConstruct // 当前类初始化完毕执行 创建队列
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }

    private class VoucherOrderHandler implements Runnable {
        String queueName = "stream.orders";
        @Override
        public void run() {
            while (true) {
                try {
                    // 获取消息队列中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 BLOCK 2000 STREAMS streams.order >
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1).block(Duration.ofSeconds(2)),
                            StreamOffset.create(queueName, ReadOffset.lastConsumed())
                    );
                    // 判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        // 如果不存在获取失败，说明没有消息，继续下一次循环
                        continue;
                    }
                    // 解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    // ACK 确认 SACK stream.orders g1 id
                     stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理订单异常",e);
                    handlePendingList();
                }
            }
        }

        private void handlePendingList() {
            while (true) {
                try {
                    // 获取pending-list中的订单信息 XREADGROUP GROUP g1 c1 COUNT 1 STREAMS streams.order 0
                    List<MapRecord<String, Object, Object>> list = stringRedisTemplate.opsForStream().read(
                            Consumer.from("g1", "c1"),
                            StreamReadOptions.empty().count(1),
                            StreamOffset.create(queueName, ReadOffset.from("0"))
                    );
                    // 判断消息获取是否成功
                    if (list == null || list.isEmpty()) {
                        // 如果不存在获取失败，说明pending-list没有消息，结束循环循环
                        break;
                    }
                    // 解析消息中的订单信息
                    MapRecord<String, Object, Object> record = list.get(0);
                    Map<Object, Object> values = record.getValue();
                    VoucherOrder voucherOrder = BeanUtil.fillBeanWithMap(values, new VoucherOrder(), true);
                    // 获取成功，可以下单
                    handleVoucherOrder(voucherOrder);
                    // ACK 确认 SACK stream.orders g1 id
                    stringRedisTemplate.opsForStream().acknowledge(queueName, "g1", record.getId());
                } catch (Exception e) {
                    log.error("处理pending-list订单异常",e);
                    try {
                        Thread.sleep(20);
                    } catch (InterruptedException ex) {
                        ex.printStackTrace();
                    }
                }
            }
        }
    }

//    private class VoucherOrderHandler implements Runnable {
//        @Override
//        public void run() {
//            while (true) {
//                try {
//                    // 获取队列中的订单信息
//                    VoucherOrder order = orderTasks.take();
//                    // 创建订单
//                    handleVoucherOrder(order);
//                } catch (Exception e) {
//                    log.error("处理订单异常",e);
//                }
//            }
//        }
//    }

    /**
     * 下单权限校验
     * @param order
     */
    private void handleVoucherOrder(VoucherOrder order) {
        // 获取用户id
        Long userId = order.getUserId();
        // 创建锁对象
        RLock lock = redissonClient.getLock("lock:order:" + userId);
        // 获取锁
        boolean isLock = lock.tryLock();
        // 判断是否获取锁成功
        if (!isLock) {
            // 获取锁失败，返回错误信息或重试
            log.error("不允许重复下单");
            return;
        }
        try {
             proxy.createVoucherOrder(order);
        } finally {
            // 释放锁
            lock.unlock();
        }
    }

    // 代理对象
    private IVoucherOrderService proxy;

    @Override
    public Result seckilVouvher(Long voucherId) throws InterruptedException {
        // 获取用户
        Long userId = UserHolder.getUser().getId();
        // 获取订单id
        Long orderId = redisIdWorker.nextId("order");
        // 执行lua脚本
        Long result = stringRedisTemplate.execute(
                SETCKILL_SCRIPT,
                Collections.emptyList(),
                voucherId.toString(),
                userId.toString(),
                String.valueOf(orderId)
        );

        // 判断结果是否为0
        int r = result.intValue();
        if (r != 0) {
            // 不为0，代表没有购买资格
            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
        }
        // 获取代理对象
        proxy = (IVoucherOrderService) AopContext.currentProxy();

        // 返回订单id
        return Result.ok(orderId);
    }

    /**
     * 创建订单
     * @param voucherId
     * @return
     */
//    @Override
//    public Result seckilVouvher(Long voucherId) throws InterruptedException {
//        // 获取用户
//        Long userId = UserHolder.getUser().getId();
//        // 执行lua脚本
//        Long result = stringRedisTemplate.execute(
//                SETCKILL_SCRIPT,
//                Collections.emptyList(),
//                voucherId.toString(),
//                userId.toString()
//        );
//
//        // 判断结果是否为0
//        int r = result.intValue();
//        if (r != 0) {
//            // 不为0，代表没有购买资格
//            return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
//        }
//        // 为0，有购买资格，把下单信息保存到阻塞队列
//        VoucherOrder voucherOrder = new VoucherOrder();
//        // 订单id
//        Long orderId = redisIdWorker.nextId("order");
//        // 用户id
//        voucherOrder.setId(orderId);
//        // 代金卷id
//        voucherOrder.setVoucherId(voucherId);
//        // 放入阻塞队列
//        orderTasks.add(voucherOrder);
//
//        // 获取代理对象
//        proxy = (IVoucherOrderService) AopContext.currentProxy();
//
//        // 返回订单id
//        return Result.ok(orderId);
//    }

    /**
     * 创建订单
     * @param
     * @return
     */
//    @Override
//    public Result seckilVouvher(Long voucherId) throws InterruptedException {
//        // 查询优惠卷
//        SeckillVoucher voucher = iSeckillVoucherService.getById(voucherId);
//
//        // 判断秒杀是否开始
//        if (voucher.getBeginTime().isAfter(LocalDateTime.now())) {
//            // 尚未开始
//            return Result.fail("秒杀尚未开始");
//        }
//
//        // 判断秒杀是否已经结束
//        if (voucher.getEndTime().isBefore(LocalDateTime.now())) {
//            return Result.fail("秒杀已经结束");
//        }
//
//        // 判断库存是否充足
//        if (voucher.getStock() < 1) {
//            // 库存不足
//            return Result.fail("库存不足");
//        }
//
//        Long userId = UserHolder.getUser().getId();
//
//        // 创建锁对象
////        SimpleRedisLock lock = new SimpleRedisLock("order:" + userId,stringRedisTemplate);
//        RLock lock = redissonClient.getLock("lock:order:" + userId);
//        // 获取锁
////        boolean isLock = lock.tryLock(1200);
//        boolean isLock = lock.tryLock(1L, TimeUnit.SECONDS);
//        // 判断是否获取锁成功
//        if (!isLock) {
//            // 获取锁失败，返回错误信息或重试
//            return Result.fail("不允许重复下单");
//        }
//
//        // 获取代理对象 (事务)
//        try {
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        } finally {
//            // 释放锁
////            lock.unLock();
//            lock.unlock();
//        }
//        // 事务提交结束再释放🔒
////        synchronized (userId.toString().intern()) {
////            // 获取代理对象 (事务)
////            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
////            return proxy.createVoucherOrder(voucherId);
////        }
//    }

    /**
     * 下单权限校验完毕，执行创建订单逻辑
     * @param voucherOrder
     */
    @Transactional
    public void createVoucherOrder(VoucherOrder voucherOrder) {
        // 一人一单
        Long userId = voucherOrder.getUserId();

            // 查询订单
            int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
            // 判断是否存在
            if (count > 0) {
                // 用户已经购买过了
                log.error("用户已经购买过一次!");
                return;
            }

            // 扣减库存
            boolean success = iSeckillVoucherService.update()
                    .setSql("stock = stock -1") // set stock = stock - 1
                    .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0) // where id = ? and stock > 0
                    .update();
            if (!success) {
                // 扣减失败
                log.error("库存不足");
                return;
            }

            save(voucherOrder);

    }
}
